US3246808A - Fluid metering apparatus having drip prevention means - Google Patents

Description

April 19, 1966 E. w. LIDELL ETAL 3,246,808

FLUID METERING APPARATUS HAVING DRIP PREVENTION MEANS Filed May 18, 1964 2 Sheets-Sheet l INVENTORS EDWIN W. LIDELL GEORGE J. BURSAK ATTORNEY April 19, 1966 E. W. LIDELL ETAL FLUID METERING APPARATUS HAVING DRIP PREVENTION MEANS Filed May 18, 1964 ii 18 i I? 2 Sheets-Sheet 2 HWW W \NVENTORS EDWIN W. LlDELL.

GEORGE J. BURSAK ATTORNEY United States Patent FLUID METERING APPARATUS HAVING DRIP PREVENTION MEANS Edwin W. Lidell, Brookiieid, and George J. Bursak, Milwaukee, Wis., assignors to Bursak Packaging Machinery Corp, Jackson, Wis., a corporation of Wisconsin Filed May 18, 1964, Ser. No. 368,127 8 Claims. (Cl. 222-330) This invention relates to a fluid metering apparatus, and more particularly resides in an apparatus for controlling the feeding of a selected volume of a fluid from a source and through distribution means, which apparatus includes means for positively halting the flow of fluid to the distribution means once the'selected volume has been discharged through the distribution means and for thereafter insuring that fluid accumulated in the distribution means will not be discharged.

In numerous modern applications it is necessary to deliver upon demandfixed, preselected volumes of a material for processing. One general area in which such 'a requirement exists is the field of flexible packaging wherein it is often desirable to introduce fluid materials (and by this is generally. meant liquids and liquids with suspended solids) to be packaged into the flexible packages as they are being formed. In many instances the volume, or the Weight which can be related to the volume, must be controlled to a greater degree of precision. Examples are thepackaging of foodstuffs which require a weight designation and the packaging of paint pigments adapted for addition to neutral bases to yield a desired color. Obviously, in the packaging of foodstuffs, supplying a lesser or a greater volume of fluid material will result in misbranding or economic lossto the processor, and that in the instance of the paint pigment additives the accuracy of the volume supplied will control the trueness of the resultant paint color.

In general, a system for feeding the fluid material to a dispensing point would include a pump to deliver the fluid under pressure from a source, distribution means generally including conduits leading to the dispensing point, and controllable valve means connected in the system between the source and dispensing point and which'functions to control the delivery of the selected volumes of the fluid to the dispensing p'oint. Unless the valve means is disposed at the precise end of the distribution means, which is generally impracticable because of interference with processing equipment to which the fluid is to be delivered, there is always some material in the conduits of the distribution means beyond the valve means after the selected volume has been dispensed and the flow halted. There is considerable danger of the fluid material in the conduits being accidentally discharged from the end of the conduits thereby upsetting the metered volume. The accidental discharge may result from the pressure of the fluid in the conduits or, in the case of a gravity feed, from the weight of the fluid.

The apparatus of this invention prevents the false delivery of excessive quantities of fluid material by including valve means actuable to positively block the flow of the fluid from the source once the selected volume has been dispensed and which further includes means which create a partial vacuum once the flow of fluid has been blocked 1 a fluid metering apparatus which positively and accurately controls the delivery of selected volumes of a fluid to a dispensing point.

It is another object of this invention to provide a fluid metering apparatus which halts the flow of the fluid once a selected volume has been dispensed and which thereafter will suck back the fluid in distributing conduits beyond the apparatus to prevent accidental discharge of excess quantities of the fluid from the conduits.

It is a further object of this invention to provide such a fluid metering apparatus including a controllable valve which in its open position permits fluid to flow from a source to a delivery conduit and which when closed halts the flow and creates a partial vacuum to draw a portion of the fluid in the delivery conduit back to the apparatus to prevent discharge of excess quantities of the fluid.

It is also an object of this invention to provide such a fluid metering apparatus including simple adjustment means to permit selection of the amount of suck-back created to accommodate fluids of various viscosities and distribution systems of varied capacities and characteristics.

It is a further object of this invention to provide a fluid metering apparatus including a plurality of valve assemblies each connectable between a source of the fluid and a dispensing point to control the delivery of fluid to the dispensing points, together with actuable means to simultaneously close each of the valve assemblies to halt the flow of fluid and to suck back fluid to the assemblies.

The foregoing and other objects will appear in the description to follow. In the description, reference is made to the accompanying drawings which for-m a part hereof and in which there is shown by way of illustration specific embodiments in which this invention may be practiced. The embodiments will be described in 'suflicient detail to enable those skilled in the art to practice this invention, but it is to be understood that other embodiments of the invention may be used and that structural changes may be made in the embodiments described without departing from the scope of the invention. Consequently, the following detailed description is not to be taken in a limiting sense; instead, the scope of the present invention is best defined by the appended claims.

In the drawings:

FIG. 1 is a view in elevation of a fluid feed system including the fluid metering apparatus of the present invention;

FIG. 2 is atop plan view of the fluid metering apparatus of FIG. 1; i

FIG. 3 is a view in vertical section taken of the line 33 of FIG. 2;

FIG. 4 is a view in vertical section similar to that of FIG. 3 but illustrating the apparatus in a closed position;

FIG. 5 is a view in vertical section through a second embodiment of a plunger assembly of the apparatus; and

FIG. 6 is a view in vertical section similar to FIG. 5 but showing the plunger assembly in a closed position.

Referring to the drawings, a pump 10 delivers a fluid to be dispensed from a source 11'to an inlet conduit in the form of a hollow conical member 12 which has a greater cross sectional area at its top than at its bottom. A can plate 13 seats with the upper peripheral edge of the conical member 12 and is secured thereto by a hexagonal nut 14. The nut 14 has a radially inward extending flange 15 which engages a ledge 16 on the cap plate 13, and the nut 14 is threadedly engaged about the upper end of the conical member 12.

The cap plate 13 supports the fluid metering apparatus which broadly comprises a plurality of plunger assemblies 17, four in number in the embodiment shown, and actuating means in the form of an air cylinder assembly 18 employed to control the opening and closing of the plunger assemblies 17. Specifically, the four plunger assemblies 17 are arrayed about the central air cylinder assembly 18 at equally spaced intervals. The cap plate 13 has four equally spaced through bores 19 each of in the plane which receives a reduced lower end portion 21) of a hollow plunger cylinder 21. The reduced end portion of each 2 cylinder 21 is journaled in a respective through bore 159 to have a lower inlet opening 22 to the hollow interior of the plunger body communicate with the hollow interior of the conical member 12.

K Each inlet opening 22 leads to an inlet passage 23 in the plunger cylinder 21 and which in turn leads to a central chamber 24. A threaded outlet opening 25 extends transversely into the central chamber 24 of the plunger cylinder 21 and a needle valve 26 is 'threadedly received in the outlet opening 25. The needle valves 26 may be of known construction and are adopted to be connected to supply conduits (not shown) which lead to the ultimate dispensing points for the fluid.

The plunger cylinder 21 is provided with an enlarged upper bore 27 above the central chamber 24 and which is of a larger diameter than that of the inlet passage 23, for reasons which will appear hereafter. A pistonin the form of a plunger guide 28 is slideably received within the upper bore 27 of each plunger cylinder 21 and is sealed with the interior of the upper bore 27 by a pair of O-rings 29 supported in annular recesses in the plunger guide 28. The plunger guide 28 has a central bore 30 which receives a plunger rod 31 that is threaded at its upper end and engaged in an internally threaded upper enlarged portion 32 of the guide 28. The plunger rod 31 projects downwardly through the central chamber 24 and the inlet passage 23 to terminate in a plunger 33. The plunger rod 31 is sealed with the central bore 30 of the guide 28 by an O-ring 34.

The plunger 33 is disposed within the hollow interior of the conical member 12 when the plunger assembly 17 is open. The outside diameter of the plunger 33 is slightly less than. that of the inlet passage 23 and the plunger 33 is adapted to be retracted within the inlet passage 23 when the plunger assembly 17 closes. An O-ring 35 is mounted in an annular recess 36 in the outer periphery of the plunger 33 to wipe the walls of the inlet passage 23 as the plunger .33 is retracted.- Y

The upper enlarged portion of the plunger guide 28 seats upon the upper end of the plunger cylinder 21 when the plunger assembly 17 is in a fully open position. The position of the plunger 33 when the plunger guide 28 is in its lowermost open position may be varied by means of the threaded engagement of the rod 31 and the guide 28. Once the proper position has been determined the rod 31 is retained by a jam nut 37 which surrounds the threaded end of the plunger rod 31 and rests against the upper end of the plunger guide 28.

The air cylinder assembly 18 comprises an air cylinder 38 having a projecting stud 39 at its bottom which is threadedly engaged in a tapped hole 40 provided in 'the centerof the cap plate 13. A piston 41 operates in the air cylinder 38 and has its piston rod '42 extending upwardly and projecting through the cylinder 38. Upper and lower air ports 43 and 44, respectively, are provided in the cylinder 38 and are adapted to admit air under pressure either above or below the piston 41, as desired.

The extending upper portion of the piston rod 42 is threaded to receive a cover plate 45. The cover plate 45 has four equally spaced notches 46 in its outer periphery and each notch is adapted to engage an annular recess 47 provided in the enlarged portion 32 of each plunger guide 28. The vertical position of the cover plate 45 on the piston rod 42 may be varied and once selected may be retained by a jam nut 48.

In operation, the fluid to be dispensed is pumped by the pump 10 from the source 11 to fill the conical member 12. With the piston 41 in its lowest position, the plunger assemblies 17 are open with the elements assuming the positions shown in FIG. 3. The plunger guides 28are in their lowest position with the enlarged upper portions 32 resting upon the cylinders 21. The plungers 33 are disposed in the fluid filling the conical member 12. The

fluid under pressure in the conical member 12 is then free to pass through the inlet openings 22 and along the inlet passages 23 and central chambers 24 to the outlet openings 25 to enter the needle valve 26 and pass thence to the point of distribution. When a desired preselected quantity of the fluid has passed through each outlet opening 25, the air cylinder assembly 18 is actuated by admitting air under pressure through the lower air port 44 thereby causing the piston 41 and piston rod 42 to move suddenly upwardly. The upward movement of the piston 41 and piston rod 42 carries with it the four plunger guides 28. As the plunger guides 28 are moved upwardly each of the plungers 33 are retracted into their respective inlet passage 23 to halt the flow of fluid to the needle valve 26.

This action 'would be suificient to stop the dispensing of the fluid except that the inlet passages 23, the central chambers 24, the needle valves 26 and the ultimate distribution lines will be full of fluid which can find its way to the dispensing points and be unintentionally discharged either because of the pressure of the accumulated fluid or by the effects of gravity. To prevent this, the apparatus of this invention creates a partial vacuum in the cylinders 21 to result in a pressure diflerential which will draw fluid back into the cylinders 21 from the needle valve 26 and the distribution lines connected thereto. This occurs by the withdrawal of the plunger guides 28 within the upper bores 27 of the cylinders 21. Since the volume vacated as each plunger guide 28 withdraws is greater than the volume displaced by the upward movement of a plunger 33 through the inlet passage 23, a suck-back is created to prevent the accidental discharge of the accumulated fluid which would destroy the accuracy of the metered volume. The closed position of the plunger assemblies 17 is shown in FIG. 4.

When it is again desired to dispense the selected volume of the fluid, the air beneath the piston 41 is evacuated from thecylinder 38 through the lower a-ir port 44 and air under pressure is admitted through the upper air port 43. The piston 41 and its piston rod'42 will be moved downwardly to open all of the plunger assemblies 17 and permit the flow of fluid to the dispensing points to begin anew.

' The pump 10 may be employed to maintain a continuous supply of the fluid to the conical member 12 so that the pressure of the fluid at the top of the conical member 12 is constant. The air cylinder assembly 18 is then used to exclusively control the volume of the dispensed fluid by opening and closing the plunger assemblies 17. Alternately, 'both' the pump 10 and the air cylinder assembly 18 may be used in unison to dispense the selected volume. That is, once the conical member 12has been filled with the fluid the air cylinder assembly 18 can be actuated to open the plunger assemblies '17 and at thesame time the pump 10 can be'driven to begin feeding the fluid through the outlet openings 25. The plunger assemblies 17 then remain open until the selected volume has been fed bythe pump 10 at which time the pump 10 is stopped and the air cylinder assembly 18 is actuated to close the plunger assemblies 17.

By varying the position of the cover plate 45 on the piston rod 42 and by varying the position of the plunger rods 31 in the guides 28, adjustment of the amount of "travel in the withdrawal stroke of the guides 28 may be achieved and the extent of the suck-back may be varied. In such manner, the apparatus may be adjusted to accommodate fluids having diflerent characteristics of flow and ultimately distribution systems of various configurations. Generally, fluids of low viscosity require a short travel of the guide 28 and fluids of larger viscosity and particularly those which include suspended solids require a larger travel to produce the necessary amount of suckback.

Referring now to FIGS. Sand 6, there is shown therein an alternate embodiment of a plunger assembly for use in the apparatus of this invention. Specifically, a plunger rod49 is slideably received in the central through bore 50 of a plunger guide 51 similar to the guides 28, and extends through the plunger guide 51 to terminate at its upper end in a threaded portion that mounts a washer 52. A compression spring 53 is biased between the washer 52 and the upper end of each plunger guide 51. An O-ring 54 is mounted about the plunger rod 49 to work within the central bore 50 of the plunger guide 51. Each plunger rod 49 is also provided with an upset annular shoulder 55 which normally seats against the lower end of the plunger guide 51 under the urging of the compression spring 53.

The lower end of the plunger rod 49 terminates in a plunger 56 having a resilient valve seat 57 mounted thereon and adapted to seat upon the inlet opening 22 of the plunger cylinder 21 to close the entrance to the inlet passage 23. An O-ring 58 is supported about the plunger 56 to work in the inlet passage 23.

The operation of the embodiment of FIGS. 5 and 6 is similar in most respects to that of the embodiment of FIGS. 1-4. However, the actuation of the air cylinder assembly 18 to close the plunger assemblies 17 will cause the plunger guides 51 and rods 49 to move upwardly in unison until each valve seat element 56 closes with its respective inlet opening 22. Further upward movement of the piston 41 will carry the plunger guides 51 upwardly independently of the rods 49 and the volume vacated by the continued withdrawal of the guides 51 will result in the desired suck-back action. The open and closed positions of the alternate plunger assembly are shown in FIGS. 5 and 6, respectively.

Again, by varying the position of the cover plate 45 on the piston rod 42, the amount of the suck-back can be adjusted for best results in the environment for the fluid being dispensed.

Throughout, the term fluids has been employed to describe the type of material upon which the apparatus of this invention is operative. It is not intended by the use of this term to limit the range of applicability of the apparatus. Fluids can encompass liquids and liquids with suspended solids, both minute and substantial, and other forms of material whichare capable of being fed through the apparatus and are responsive to the suck-back action produced.

Any suitable actuating means such as a hydraulic cylinder or a solenoid may be used in place of the air cylinder assembly 18. Likewise, any form of pump including a reciprocating piston may be employed to initially feed the fluid to the hollow conical member 12; or a gravity feed to the member 12 may be used.

It will be seen from the foregoing description that an apparatus in accordance with this invention provides a simple yet eflicient means for positively controlling the dispensing of selected volumes of fluids with accuracy. While the invention is useful for controlling the dispensing of a fluid generally, it can be particularly advantageously employed for dispensing fluids to flexible packages, blister packages, and rigid containers. When used in connection with flexible or blister packaging the suck-back action will prevent any dripping of the fluid which could contaminate the seals of the packages and destroy their effectiveness.

We claim:

1. In an apparatus for controlling the dispensing of a selected volume of a fluid from a source of the fluid under pressure to a point of distribution of the fluid, the combination comprising: a hollow cylinder having an inlet communicating with said source, an outlet communicating with said point of distribution, a first passage connecting said inlet and said outlet, and a second passage communicating with said first passage beyond said inlet and of a greater cross section than said first passage; plunger means movable in said first passage between an open position in which said inlet is open for the passage of fluid therethrough and a closed position in which said plunger means obstructs said first passage to halt the flow of fluid to said outlet; piston means movable in said second passage and adapted when withdrawn to vacate a volume in said cylinder greater than that displaced by movement of said plunger means to said closed position whereby a partial vacuum is created to draw fluid into said cylinder through said outlet; and actuating means adapted when actuated to move said plunger means to said closed position and to withdraw said piston means, whereby the dispensing of fluid in excess of said selected volume is prevented.

2. In an apparatus for controlling the dispensing of a fluid from an input conduit connected to a source of the fluid to an output conduit connected to a point of distribution of the fluid, the combination comprising: a cylinder having an open inlet end communicating with said input conduit, an outlet communicating with said output conduit, and a first passage connecting said inlet and said outlet; plunger means movable between an open position in which said inlet isopen for the passage of the fluid therethrough and a closed position in which said plunger means obstructs said first passage to prevent further flow of the fluid to said outlet; vacuum means including a second passage in said cylinder means communicating with said outlet and piston means movable in said second passage and operable upon said plunger means to move the same; and actuating means adapted when actuated to move said piston means to move said plunger means to said closed position and to retract said piston means within said second passage to create a vacuum within said cylinder to draw fluid into said cylinder through said outlet.

3. In an apparatus for controlling the dispensing of a selected volume of a fluid from a source of the fluid to points of distribution of the fluid, the combination comprising: reciprocating actuating means including a driven rod; a transverse plate mounted on said driven rod; a plurality of cylinders each having an inlet communicating with said source and an outlet communicating with one of said points of distribution; plunger means movable in each cylinder between an open position in which said inlet is open for the passage of fluid therethrough and a closed position in which said plunger means obstructs the passage between said inlet and outlet to halt the flow of fluid to said outlet; and piston means movable in each cylinder and operable on said plunger means to move the same, said piston means being adapted when withdrawn to vacate a volume in a respective cylinder and thereby create a partial vacuum after said plunger means obstructs said cylinder to draw fluid into said cylinder through said outlet; said cylinders being spaced equally about said driven rod, to have said piston rneans disposed parallel with said driven rod, said piston means each having a portion which projects outwardly of its cylinder and which is attached to said transverse plate whereby actuation of said actuating means after said selected volume has been dispensed withdraws said piston means and moves said plunger means to said closed positions.

4. An apparatus in accordance with claim 3 together 'with means for varying the longitudinal position of each plunger means relative to its piston means and means for varying the position of said plate on said driven rod for adjustment of the amount of said vacuum created.

-5. In an apparatus for controlling the dispensing of a selected volume of a fluid from an input conduit connected to a source of the fluid to an output conduit connected to a point of distribution for the fluid, the combination comprising: a cylinder having an open inlet end communicating1with said input conduit, an outlet communicating with said output conduit, a first passage connecting said inlet and said outlet, and a second passage communicating with said first passage beyond said inlet and having a greater cross sectional area than said first passage; a guide slideably received within said second passage; a plunger connected to said guide for concurrent movement and operable in said first passage, said guide and said plunger being movable between an open position in which said inlet is open for the passage of fluid through said first passage to said outlet and a retracted position in which said plunger moves into said first passage to obstruct the same and halt the flow of fluid to said outlet and in which said guide moves within said second passage to create a partial vacuum that draws fluid from said outlet conduit to said cylinder; and actuating means adapted when actuated to move said guide and said plunger to said retracted position upon the completion of the dispensing of said selected volume of fluid.

6. In an apparatus for controlling the dispensing of a selected volume of a fluid from an input conduit supplied with fluid under pressure from a source to a plurality of output conduits connected to points of distribution for the fluid, the combination comprising: a plurality of cylinders each having an open bottom forming an inlet communicating with said input conduit, an outlet communicating with one of said output conduits, a first passage connecting said inlet and said outlet, and a second passage of greater cross sectional area than said first passage and being aligned with said first passage beyond said inlet; a guide slideably received within each of said second passages; a plunger rod extending from each guide through said first passage and having a cross sectional area less than that of said first passage; a plunger secured to the extending end of each plunger rod and of a cross sectional area substantially that of said first passage, said guide and said plunger having an open position in which said guide is bottomed in said second passage and said plunger is disposed within said input conduit for the passage of fluid from said inlet to said outlet; and reciprocating actuating means including a driven rod connected to said guides to move said guides when actuated to retract said plungers within said first passages to halt the flow of fluid through said first passages and to move said guide within said second passages to create a partial vacuum to draw fluid from said output conduits into said cylinders.

7. In an apparatus for controlling the dispensing of a selected volume of a fluidyfrom an input conduit connected to a source of the fluid to an output conduit connected to a point of distribution for the fluid, the combination comprising: a cylinder having an open inlet end communicating with said input conduit, an outlet communicating with said output conduit, a first passage connecting said inlet and said outlet, and a second passage communicating with said first passage beyond said inlet; a guide slideably received within said second passage; a plunger extending through said first passage and yieldably connected to said guide, said plunger being movable between an open position in which said inlet is open for the passage of fluid through said first passage to said outlet and a closed position in which said plunger seats against said inlet to block the same; and actuating means operable on said guide and adapted when actuated to move said guide in said second passage to move said plunger to said closed position and to thereafter continue to move said guide within said second passage to create a partial vacuum, whereby fluid is drawn into said cylinder from said output conduit.

8. In an apparatus for controlling the dispensing of a selected volume of a fluid from an input conduit supplied with fluid under pressure from a source to a plurality of output conduits connected to points of distribution for the fluid, the combination comprising: a plurality of cylinders each having an open bottom forming an inlet communicating with said input conduit, an outlet communicating with one of said output conduits, a first passage connecting said inlet and said outlet, and a second passage communicating with said first passage beyond said inlet; a guide slideably received within each of said second passages; a plunger rod slideably received in a through bore in each of said guides, said plunger rod having an upper end which extends above said guide and alower end which extends through said first passage; a plunger secured to the lower end of each plunger rod of a cross sectional area greater than said inlet; a compression spring biased between the upper end of each guide and shoulder means on the upper extending end of said plunger rod, said guide and said plunger having an open position in which said guide is bottomed in said second passage and said plunger is disposed within said input conduit for passage of fluid from said inlet to said outlet; and reciprocating actuating means including a driven rod connected to said guides to lift said guides when actuated to retract said plungers to seat the same against said inlets and thereby halt the flow of fluid through said inlets and to thereafter continue to lift said guides against said springs to move said guides within said second passages to create a partial vacuum to draw fluid from said output conduits into said cylinders.

References Cited by the Examiner UNITED STATES PATENTS 3/1926 Fenton 222-380 2,839,226 6/1958 Ross 14lll7 X M. HENSON, WOOD, JR., Primary Examiner.

Claims (1)

1. IN AN APPARATUS FOR CONTROLLING THE DISPENSING OF A SELECTED VOLUME OF A FLUID FROM A SOURCE OF THE FLUID UNDER PRESSURE TO A POINT OF DISTRIBUTION OF THE FLUID, THE COMBINATION COMPRISING: A HOLLOW CYLINDER HAVING AN INLET COMMUNICATING WITH SAID SOURCE, AN OUTLET COMMUNICATING WITH SAID POINT OF DISTRIBUTION, A FIRST PASSAGE CONNECTING SAID INLET AND SAID OUTLET, AND A SECOND PASSAGE COMMUNICATING WITH SAID FIRST PASSAGE BEYOND SAID INLET AND OF A GREATER CROSS SECTION THAN SAID FIRST PASSAGE; PLUNGER MEANS MOVABLE IN SAID FIRST PASSAGE BETWEEN AN OPEN POSITION IN WHICH SAID INLET IS OPEN FOR THE PASSAGE OF FLUID THERETHROUGH AND A CLOSED POSITION IN WHICH SAID PLUNGER MEANS OBSTRUCTS SAID FIRST PASSAGE TO HALT THE FLOW OF FLUID TO SAID OUTLET; PISTON MEANS MOVABLE IN SAID SECOND PASSAGE AND ADAPTED WHEN WITHDRAWN TO VACATE A VOLUME IN SAID CYLINDER GREATER THAN THAT DISPLACED BY MOVEMENT OF SAID PLUNGER MEANS TO SAID CLOSED POSITION WHEREBY A PARTIAL VACUUM IS CREATED TO DRAW FLUID INTO SAID CYLINDER THROUGH SAID OUTLET; AND ACTUATING MEANS ADAPTED WHEN ACTUATED TO MOVE SAID PLUNGER MEANS TO SAID CLOSED POSITION AND TO WITHDRAW SAID PISTON MEANS, WHEREBY THE DISPENSING OF FLUID IN EXCESS OF SAID SELECTED VOLUME IS PREVENTED.

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